Azido-Functionalized Aromatic Phosphonate Esters in POSS-Cage-Supported Lanthanide Ion (Ln = La, Nd, Dy, Er) Coordination.

Within this work, a modified preparation of diethyl 4-azidobenzylphosphonate () is presented and the family of 4- or 4'-azido-substituted aromatic phosphonate esters is increased by three new ligand platforms: diisopropyl 4-azidobenzylphosphonate (), diisopropyl ((4'-azido-[1,1'-biphenyl]-4-yl)methyl)phosphonate (), and diisopropyl 4-azido-2,3,5,6-tetrafluorobenzylphosphonate (), which exhibit an anomalous splitting of the N stretching vibrations. Subsequent coordination to the generated POSS (polyhedral oligomeric silsesquioxane)-cage-supported lanthanide precursors [(Ln{POSS})(THF)] (-) (Ln = La, Nd, Dy, Er; R = Bu, Ph; = 0, 1) yields complexes of the general formula [Ln{POSS}(-)()(THF)] (-) ( = 2, 3; = 0, 1; = 0-2) retaining the azide unit for future semiconductor surface immobilization. Because the latter compounds are mostly oils or viscous waxes, preliminary solution-state structure elucidations via DOSY-ECC-MW estimations have been carried out which are in accordance with H NMR integral ratios as well as solid-state structures, where available. Moreover, the optical properties of the Nd, Dy, and Er derivatives of complexes - are examined in the visible and NIR spectral regions, where applicable.